STORMWATER

STORMWATER – WATERWAYS, WETLANDS AND DRAINAGE GUIDE
Service Areas: Stormwater, Science Communication

Having edited and designed the original Part B of the Christchurch City Council’s ‘Waterways Wetlands and Design Guide’, in 2012 we were once again asked to edit and format an updated Chapter 6, which deals with stormwater treatment.

Designed to clarify Council’s preference for stormwater treatment and provide updated calculations for determination of first flush volume, this amended chapter will be essential for anyone dealing with stormwater in Christchurch. You can download a copy of the chapter from here .

TRANZLINK PONDS TREATMENT EFFICIENCY
Service Areas: Stormwater, Applied Research

Interested in measuring the performance of their stormwater treatment systems, the Christchurch City Council commissioned EOS Ecology to assess the treatment efficiency of the Tranzlink ponds which treat stormwater in a predominantly industrial catchment.

The EOS team undertook a baseline dry weather study of the treatment system and then developed a stormwater sampling programme to monitor contamination loadings in the influent and effluent flows for the combined wetland and first flush basin, as well as for the wetland portion of the system. EOS’s programme was designed to capture information on the first flush, as well as prolonged storm events; with samples collected via multiple automatic samplers and tested for pollutants such as heavy metals, chlorides, nutrients, and suspended solids. Our results were able to determine treatment efficiency during small and large storm events.

CASHMERE STREAM SEDIMENT SOURCES
Service Areas: Stormwater, Urban Ecology

Community concerns regarding sediment in Cashmere Stream led Environment Canterbury (ECan) to commission EOS Ecology to undertake a detailed study of the stream’s sediment inputs.

The scientists at EOS designed an extensive sampling programme to pinpoint the source and types of sediment entering the stream. Encompassing the monitoring of 81 sites during one dry and three rain events, this project identified the top five contributors of sediment to Cashmere Stream. This information is key to dealing with sediment inputs on a catchment-wide basis which will ultimately also benefit the downstream Heathcote River and Avon-Heathcote Estuary/Ihutai.

NORTHWOOD STORMWATER BASIN MONITORING
Service Areas: Stormwater

Stormwater basins are often built but rarely tested. The Christchurch City Council decided to test the performance of two recently constructed basins at Northwood. During a number of discrete rain events, EOS technicians did what they do best – go out in the field and get wet – to collect water samples for water quality testing. Samples from inflows and outflows for both basins, as well as the Styx River (the receiving environment) were tested for the usual suspects in urban areas – suspended sediment, heavy metals such as arsenic and zinc, and nutrients (nitrogen and phosphorus).

AIDANFIELDS STORMWATER MONITORING
Service Areas: Stormwater, Applied Research

With both an interest and a legal obligation to monitor stormwater quality in the Aidanfield development area and its effect on the receiving environment of Cashmere Stream, the Christchurch City Council commissioned EOS Ecology to develop and undertake comprehensive stormwater monitoring within the Cashmere Stream catchment.

With both an interest and a legal obligation to monitor stormwater quality in the Aidanfield development area and its effect on the receiving environment of Cashmere Stream, the Christchurch City Council commissioned EOS Ecology to develop and undertake comprehensive stormwater monitoring within the Cashmere Stream catchment.